This invention relates to a method of detecting a leak in any one of the vacuum-type circuit interrupters of a high-voltage vacuum circuit breaker comprising a plurality of series-connected interrupters located within a housing of the circuit breaker containing pressurized insulating gas.
The following references are of interest with respect to this invention: U.S. Pat. Nos. 3,403,297-Crouch; 3,472,981-McCarty et al; 3,626,125-Tonegawa; 3,641,359-McCarty; 3,814,885-Sofianek.
One way of checking a vacuum interrupter for a leak is to apply a high potential across its terminals. If the inturrupter contains a leak which has allowed the pressure therein to rise to a level of 0.01 torr or higher, then the high potential will ordinarily produce a sparkover within the interrupter, which can be readily detected. But in prior designs of the type of vacuum circuit breaker that I am concerned with, i.e., high-voltage vacuum circuit breakers that comprise series-connected interrupters located within a closed tank filled with pressurized gas, the terminals of the interrupter may not be accessible unless all the insulating gas in the tank is removed, the tank is opened, and the circuit breaker pole is significantly dismantled. This procedure, of course, can be time-consuming and therefore expensive.